Recently, a fingerprint identification technology has been applied to a variety of electronic products. By using the fingerprint identification technology, the user's fingerprint can be inputted into an electronic product and saved in the electronic product. For unlocking the electronic product, the user has to input the fingerprint through a fingerprint identification module. The way of unlocking the electronic product by the fingerprint identification technology is faster and more user-friendly than the way of manually inputting the password. Consequently, the fingerprint identification technology is favored by many users, and the demands on the fingerprint identification module are gradually increased.
Generally, a fingerprint identification module comprises a fingerprint sensor, a protective cover, a metallic ring and a circuit board. The fingerprint sensor is disposed on and electrically connected with the circuit board. The fingerprint sensor is used for sensing the user's finger and retrieving the information of the user's finger. The protective cover is used for covering the fingerprint sensor in order to protect the fingerprint sensor. The user's finger is only permitted to touch the protective cover. Since the user's finger is not directly contacted with the fingerprint sensor, the fingerprint sensor is not easily damaged. The metallic ring is sheathed around the protective cover. The metallic ring is used for transferring the charges of the user's finger in order to facilitate the operations of the fingerprint sensor.
A method of assembling a conventional fingerprint identification module will be described as follows. Firstly, the fingerprint sensor is placed on the circuit board, and the fingerprint sensor is electrically connected with the circuit board. Then, the protective cover is stacked on the fingerprint sensor, and the protective cover and the fingerprint sensor are adhered on each other. After the metallic ring is sheathed around the protective cover, the conventional fingerprint identification module is assembled.
In the above assembling method, the fingerprint sensor is obtained by cutting a sensing strip. A process of producing the fingerprint sensor will be described as follows. Firstly, the sensing strip is fixed on a base plate through an adhesive. Then, the sensing strip is cut to produce plural fingerprint sensors according to a predetermined size. The actual sizes of the plural fingerprint sensors are identical to or close to the predetermined size. In fact, the fingerprint sensor after the cutting procedure has a cutting tolerance.
FIG. 1 is a schematic view illustrating the structure of a conventional fingerprint sensor. As shown in FIG. 1, the size of a top surface 101 of the fingerprint sensor 10 is close to or nearly equal to the predetermined size. However, due to the cutting skew, the size of a bottom surface 102 of the fingerprint sensor 10 is possibly larger than the predetermined size. Although the size of the top surface 101 of the fingerprint sensor 10 is close to the predetermined size, the fingerprint sensor 10 is unable to pass the size test because the size of the bottom surface 102 of the fingerprint sensor 10 is larger than the predetermined size. Under this circumstance, the fingerprint sensor 10 is determined as unqualified product. As mentioned above, the sensing strip has to be fixed on the base plate through an adhesive during the process of producing the fingerprint sensor. After the cutting procedure is performed, residual fragments of the adhesive are readily remained on the fingerprint sensor. Since the residual fragments of the adhesive may adversely affect the operation of the fingerprint sensor, it is necessary to remove the residual fragments of the adhesive. The procedure of removing the residual fragments of the adhesive increases the time period of the overall fabricating process and reduces the fabricating efficiency.
Therefore, there is a need of providing a method for assembling a fingerprint identification module with high yield and high fabricating efficiency.